Grisly find suggests humans inhabited Arctic 45,000 years ago

In August of 2012, an 11-year-old boy made a gruesome discovery in a frozen bluff overlooking the Arctic Ocean. While exploring the foggy coast of Yenisei Bay, about 2000 kilometers south of the North Pole, he came upon the leg bones of a woolly mammoth eroding out of frozen sediments. Scientists excavating the well-preserved creature determined that it had been killed by humans: Its eye sockets, ribs, and jaw had been battered, apparently by spears, and one spear-point had left a dent in its cheekbone—perhaps a missed blow aimed at the base of its trunk.

When they dated the remains, the researchers got another surprise: The mammoth died 45,000 years ago. That means that humans lived in the Arctic more than 10,000 years earlier than scientists believed, according to a new study. The find suggests that even at this early stage, humans were traversing the most frigid parts of the globe and had the adaptive ability to migrate almost everywhere.

Most researchers had long thought that big-game hunters, who left a trail of stone tools around the Arctic 12,500 years ago, were the first to reach the Arctic Circle. These cold-adapted hunters apparently traversed Siberia and the Bering Straits at least 15,000 years ago (and new dates suggest humans may have been in the Americas as early as 18,500 years ago).

But in 2004, researchers pushed that date further back in time when they discovered beads and stone and bone tools dated to as much as 35,000 years old at several sites in the Ural Mountains of far northeastern Europe and in northern Siberia; they also found the butchered carcasses of woolly mammoths, woolly rhinoceros, reindeer, and other animals.

The Russian boy’s discovery—of the best-preserved mammoth found in a century—pushes back those dates by another 10,000 years. A team led by archaeologist Alexei Tikhonov excavated the mammoth and dubbed it “Zhenya,” for the child, Evgeniy Solinder, whose nickname was Zhenya.

The researchers flew the block of ice by cargo plane to their zoological institute at the Russian Academy of Sciences in St. Petersburg. The injuries reminded Tikhonov of more modern human hunting practices. Elephant hunters in Africa, for example, often target the base of the trunk to cut arteries, causing the animal to bleed to death. The mammoth also had injuries to its jaw that suggest the tongue was cut out. Pieces of the tusk were removed, perhaps to get ivory to produce tools. “This is a rare case for unequivocal evidence for clear human involvement,” says lead author Vladimir Pitulko, also of the Russian Academy of Sciences.

The injuries also fit with the pattern of damage seen on another butchered mammoth in Yana, also in Siberia, according to the authors. “One can almost see the blow-by-blow battle between people and mammoth fought on those frozen plains,” says Curtis Marean, a paleoanthropologist at Arizona State University, Tempe, who was not involved with the study. “The impact wounds on the bones with embedded stone fragments is conclusive evidence that people slayed this mammoth.”

The big surprise, though, is the age. Radiocarbon dates on the collagen from the mammoth’s tibia bone, as well as from hair and muscle tissue, produce a direct date of 45,000 years, the team reports online today in Science. This fits with dating of the layer of sediments above the carcass, which suggest it was older than 40,000 years. If correct, this means the mammoth was alive during the heyday of woolly mammoths 42,000 to 44,000 years ago when they roamed the vast open grasslands of the northern steppe of the Siberian Arctic, Pitulko says. Researchers also have dated a thighbone of a modern human to 45,000 years at Ust-Ishim in Siberia, although that was found south of the Arctic at a latitude of 57° north, a bit north (and east) of Moscow.

“The dating is compelling. It’s likely older than 40,000,” says Douglas Kennett, an environmental archaeologist who is co-director of the Pennsylvania State University, University Park’s accelerator mass spectrometry facility. However, he would like the Russian team to report the method used to rule out contamination of the bone collagen for dating—and confirmation of the dates on the bone by another lab, because the date is so critical for the significance of this discovery.

Mammoths and other large animals, such as woolly rhinoceros and reindeer, may have been the magnet that drew humans to the Far North. “Mammoth hunting was an important part of survival strategy, not only in terms of food, but in terms of important raw materials—tusks, ivory that they desperately needed to manufacture hunting equipment,” Pitulko says. The presence of humans in the Arctic this early also suggests they had the adaptive ability to make tools, warm clothes, and temporary shelters that allowed them to live in the frigid north earlier than thought. They had to adapt to the cold to traverse Siberia and Beringia on their way to the Bering Strait’s land bridge, which they crossed to enter the Americas.

“Surviving at those latitudes requires highly specialized technology and extreme cooperation,” Marean agrees. That implies that these were modern humans, rather than Neandertals or other early members of the human family. “If these hunters could survive in the Arctic Circle 45,000 years ago, they could have lived virtually anywhere on Earth,” says Ted Goebel, an archaeologist at Texas A&M University, College Station.